Wave generating watercraft

ABSTRACT

A watercraft is adapted to mount and support one or more wave cannons for the generation of high volume waves in a body of water, including natural beach environments lacking reliable surf. A wave cannon is an elongated tubular chamber having a closed rear end and an open front end, an anchor, a supply of compressed air, and a control valve for admitting compressed air into the elongated chamber. When mounted on a watercraft, only the interior of the chamber is exposed to corrosive water, reducing maintenance. The simple mechanics of the wave cannon further reduce expense. The watercraft may be positioned and moored at a desired offshore or lakeshore location with the open end of the chamber oriented to a shoreline. When compressed gas is discharged through the chamber, a large volume wave is generated that breaks on the shoreline.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional Application Ser. No. 60/681,502, filed May 16, 2005.

FIELD OF THE INVENTION

The present invention relates to generation of waves. More particularly, the present invention is a mobile embodiment of a wave generator for use in natural environments.

BACKGROUND OF THE INVENTION

Sports or other entertainment events that rely on waves or surf are traditionally limited to times or locations that have amenable conditions. In some locations, the surf is routine and predictable, while in others the quality of the surf may vary significantly. Further, there are many areas amendable to surf or wave sports where there may be little or no wave or surf action, as with certain east coast US or lakeside beaches.

The state of California hosts some of the more predictable surfing beaches in the continental United States. The beaches of Florida are somewhat unpredictable, and tend to be more active and stronger than those higher on the east coast. The beaches higher on the east cost may be relatively calm or moderate, with only occasional periods of challenging surf. Nevertheless, beaches such as those on the east coast of the United States might otherwise be suitable for surfing sports if the surf were to be both reliable and substantial.

Some surfers approach this problem with attempts to use waves generated by the wake of a large vessel or a separate tow at speed. This approach requires a vessel or a tow to be of substantial displacement in order to generate a suitable wave for surfing; in addition, it may involve considerable energy consumption and a degree of unpredictability in wake generation. In one example, surfers near Galveston, Tex. take advantage of shipping traffic and surf the wakes of underway supertankers; of course, this is impractical for the purposes described herein.

A conventional approach involves a plow device designed to be drawn along permanent tracks located within a body of water. While potentially suitable for pools or otherwise placid lakes, this somewhat complicated arrangement is impractical for many natural environments, particularly natural ocean beaches where marine items might obstruct the track. A similar approach is a wave generating device mounted onto the hull of a small boat or towed behind. The device includes a curved flow forming portion capable of displacing water and creating waves somewhat perpendicular to the direction of the boat. Of course, such a boat would require significant maneuvering space for clear navigation and hazard avoidance, and would be difficult to use to generate waves on a beach.

Another conventional approach involves an unmoored vessel that generates waves by dumping water onto a submerged platform attached to the side hull of the vessel. The platform is shaped so as to create a wave form in the deflected water. Internally, the vessel includes an open top water tank with a pumping system to fill the tank from the surrounding water. Hydraulic actuators and a supporting hydraulic system are required to elevate a waterproof (sealed) floor or platform of the tank. As the platform is elevated, the water is spilled out of the top of the tank and onto the submerged platform, deflecting water into a wave form. A thruster is required to hold the vessel in place during water dumping or the vessel will move and the kinetic energy of the wave will be reduced. Although this approach may be used in a natural environment, its extensive mechanical systems would be expensive and subject to exposure to corrosive water. For example, an embodiment capable of dumping sea water should include a sea chest intake, pipes, pumps, valves, and a tank system, all fabricated from a corrosion resistant material such as monel, copper-nickel alloys, or bronze. The hydraulic system and actuators must include substantial components (e.g., hydraulic pump, tubing, actuator, etc.) to lift the weight of an apparently large volume of water. Further, elevating liquids in an open tank on a vessel will raise the center of gravity, and increase the moment with the center of buoyancy, affecting the stability characteristics of the vessel. The partially filled tank, with its free surface and open top can be further destabilizing. Accordingly, the vessel must be rather large to support the unusual instability, or require some form of stabilization, such as ballasting.

Another approach is a mobile “wave effect” device, which is capable of being moved about on land and assembled where desired. This device does not involve real waves, but wave forms that simulate the effect of a wave. It relies on a mold or wave-shaped shell, typically fabricated of fiberglass, and pumps that force water over the wave mold to create sufficient laminar flow for in-place surfing. Of course, this approach is somewhat limited and does not incorporate the natural environment into the artificial waves.

Thus, a simple device for creating reliable and substantial surf in a natural beach environment would increase the attractiveness and commercial potential for many beaches. At the same time, such a device should be stable, inexpensive, and mobile.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to overcoming the drawbacks of conventional approaches and to creating high volume waves sufficient to support surf dependent sports, even in natural environments that have otherwise unreliable or inadequate surf. In the present invention, a mobile watercraft bearing equipment capable of generating waves is placed in a secure manner at a desired point located off shore. Equipment onboard the watercraft then operates to generate waves or swells directed to the shoreline with improved vessel stability. Preferably the present invention includes one or more pneumatic wave cannons mounted low within the hull of the watercraft for the generation of swells, waves, and/or currents, as may be desired for the application. A wave cannon is a wave generating device as disclosed in U.S. Pat. No. 5,833,393 to Carnahan et al., which is hereby incorporated by reference.

In the open ocean, surface waves are primarily created by winds that cause variations in surface pressure. Wind duration, strength, and surface coverage area contribute to the resulting, somewhat sinusoidal wave. As a wave reaches a point where the water depth is less than half of the wavelength, then friction from the bottom begins to affect the wave. The wave energy acts to preserve its original form, resulting in a taller wave crest. Friction also slows the progression of the wave in a manner that affects lower portions of the wave more than upper portions, distorting the sinusoidal pattern. When the depth becomes sufficiently shallow, then the upper crest peaks and proceeds forward, while the lower portion slows to such an extent that the wave breaks. This wave formation and breaking action is attractive and valuable to surf sports.

In contrast, the wave cannon transfers energy from the escape or release of compressed gas or air into water to create swells or waves. The wave cannon is notable for the high amount of energy transferred and for the resulting large volume waves. Notably, the wave cannon involves relatively simple supporting infrastructure: a source of compressed air and a discharge tube or elongated chamber.

The '393 disclosure by Carnahan et al. identified examples of where a wave cannon might be used in natural environments. In particular, this disclosure discussed fixing or anchoring submerged cannons (i.e., the elongated chambers of a wave cannon), which would be supplied by an air compressor and supporting equipment located onshore. This arrangement required pilings to anchor the elongated chambers and piping against the strong reaction forces during discharge. Pressurized gas reservoirs and compressors were located onshore to support the elongated chambers located offshore. The piping and elongated chambers were completely exposed to the marine environment, while maintenance of these elongated chambers and piping required removal or the use of undersea diving mechanics. Therefore, the permanent installation of chambers and piping underwater may share certain aspects with some of the conventional approaches described above.

Accordingly, the present invention is a watercraft adapted to support one or more wave cannons for the generation of high volume waves in bodies of water, including artificial surf in natural beach environments. A mobile, waterborne wave canon enables locating a wave generator at a desired time and place. When not in use, the present invention may be relocated or berthed for storage or maintenance. This feature is desirable because it accommodates the need to supplement natural surf conditions on an as-needed basis, as identified above. Compressed air may be stored or generated on the vessel. The simple design of the wave cannon, which exposes only the interior of the elongated chamber or discharge tube to the water, overcomes many challenges presented by conventional solutions.

Thus, a watercraft configured according to the present invention may mount a water cannon or other wave generator so as to be capable of generating swells or waves.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the present invention.

FIG. 2 is a top view of an embodiment of the present invention while in use.

FIG. 3 is a perspective view of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As introduced above, the present invention is an apparatus for generating high volume waves in a body of water; in particular, a watercraft is adapted to mount and support one or more wave cannons for the generation of artificial surf in natural environments. As disclosed in the '393 patent, a wave cannon is simply an elongated tubular chamber having a closed rear end and an open front end, an anchor, a supply of compressed air, and a control valve for admitting compressed air into the elongated chamber.

The watercraft may be any one of a wide variety of crafts having sufficient space, rigidity, and displacement. The watercraft should be suited to the topography of interest, the generally expected sea conditions of the body of water, and the overall circumstances of application. For example, in some embodiments, the watercraft may be a powered service or utility type vessel, capable of rapid relocation to accommodate changes in conditions. In other embodiments, an inexpensive, un-powered barge or lighter may be appropriate, typically providing a keyway, push block, or some other means for relocation by a tug or other vessel.

FIG. 1 is a side view of a relatively simple embodiment of the present invention showing watercraft 100 as barge, with hidden features shown by broken lines. Elongated tubular chamber 7 is mounted onto watercraft 100 by back anchor 18 and chamber anchors 9 in a substantially horizontal or slightly angled orientation. Chamber 7 is in fluid communication with water 21 through front end 7A of chamber 7, which is shown as extending through hull of watercraft 100 in a desired direction. Chambers 7 may be anchored or supported by keel 34 or other sufficiently rigid portions of watercraft 100, such as hull girders, struts, ties, ribs, etc. Optionally, back anchor 18 may include integrated conventional recoil force systems, such as slide mounts, recoil brakes, etc. In a simple design, however, chambers 7 may simply be pipes mounted onto the hull of watercraft 100.

Note that although water may enter chamber 7 through front end 7A, the interior of chamber 7 is the only surface or equipment exposed to surrounding water 24, reducing corrosion of the wave generating system. Optional chamber cover 34 may be used when chamber 7 is not in use. As shown, back anchor 18 accommodates recoil of chamber 7 during discharge, back anchor 18 being mounted onto keel 31. Preferably, watercraft 100 is anchored or moored during use. Chocks 52 and bitts 51 may be used for such mooring. Thus, watercraft 100 provides structural support for chamber 7 for storage, discharge, and transportation from site to site.

A supply of compressed air is provided by at least one pressure storage tank 2 and piping 4, creating fluid communication of compressed air from pressure storage tank 2 to rear end 7B of chamber 7. Within piping 4 is mounted control valve 5 for controlling air to chamber 7. As described in '533 to Carnahan, actuation of control valve 5 releases compressed air into rear end 7B of chamber 7, expelling water from chamber 7 out front end 7A and creating a wave 24 (not shown).

Multiple chambers 7 may be mounted onto a single watercraft 100. Preferably, however, the distribution of chambers 7 will be symmetric if simultaneous discharge is desired. Such coordinated or simultaneous discharge will concentrate the energy transfer for better wave characteristics. Multiple chambers 7 may be situated symmetrically with respect to the centerline of watercraft 100 for improved stability.

In use, elongated chambers 7 are preferably, though not necessarily, oriented perpendicularly to shoreline 29 (not shown). Chamber front end 7A is preferably, though not necessarily, located in the stern of watercraft 100 (i.e., directed aft), with chamber 7 running longitudinally, along the same dimension as keel 31. During discharge, a reaction force is transferred to watercraft 100 via back anchor 18, as further discussed below. By this orientation, the reaction force of discharging chambers 7 drives watercraft 100 in the normal direction of forward propulsion, minimizing instability.

Watercraft 100 may include optional integrated air compressor 1 for refill of pressure storage tank 2. Alternatively, an embodiment may simply include sufficient storage capacity in one or more pressure storage tanks 2. Thus, when the supply of compressed air is exhausted, watercraft 100 might be moved to a source of compressed air for refill.

Preferably, however, air compressor 1 includes a power source, such as a diesel generator with appropriate fuel storage, which brings power for other services on watercraft 100. Alternatively, air compressor 1 may simple be a air compressor having its own power source (e.g., diesel powered air compressor.) Those skilled in the art may readily select such additional auxiliary equipment as appropriate or desired for the size and contemplated use of the watercraft 100, such as control systems, lighting, fire suppression, ballasting systems, thrusters, communication equipment, observation and navigation equipment, davits, emergency rescue gear, etc. Depending on the vessel type of watercraft 100, some of the foregoing equipment may already be required for other purposes.

As introduced in reference to FIG. 1, watercraft 100 will include structure and equipment for temporarily fixing watercraft 100 in place, such as bitts 51, chocks 52, or other such portions of mooring system 50 (not shown). With reference to the top view of FIG. 2, upon watercraft 100 reaching a desired location and orientation with shore 29, watercraft 100 may be anchored or moored in place with mooring system 50. Mooring system 50 may vary widely, depending on the embodiment and circumstances. Mooring system 50 may comprise conventional temporary anchoring or deck tackle, such as lines or chains for tying to bollards or buoys, jack leg lifts, a combination anchor and ballasting submergence system (e.g., using ballast valve 60 to flood spaces within watercraft 100), helical mooring systems, etc., so long as it is adapted to restrain watercraft 100 in position during discharge of chambers 7. That is, mooring system 50 should be adapted to maintain the location of watercraft 100, which will tend to move forward for aft discharge of chambers 7 due to the reaction force.

FIG. 2 depicts an embodiment of the present invention 100 in operation. A shoreline 29 of a typical beach is shown. Watercraft 100 is moored using a four point mooring system 50. A suggested location for operation might be a beach having multiple hotels 102, such that the expense of the present invention may be borne by multiple parties within the tourism industry. Exhausting compressed air 25 demonstrates the genesis of a swell. As waves 24 radiate to shoreline 29, the increasingly shallow topography results in a breaking action, creating surf. The escaping gas and water generate a recoil force against the chamber 7. As noted above, the present invention may transfer a portion of recoil force to a recoil force system, and then the remainder of the recoil force to the structure of the watercraft 100. If wave 24 is generated off the stern of watercraft 100, it is forced forward. This forward movement is restrained by mooring system 50. If the need for waves is recurrent, then mooring buoys or other attachment points for watercraft 100 may be provided.

Given the shallowness of many shorelines, in many embodiments, preferably watercraft 100 will be of shallow draft. A flat or partially flat bottom may be appropriate for particularly shallow embodiments. In some embodiments, watercraft 100 may incorporate the ability to flood buoyancy tanks to submerge partially. In that case, a flat or partially flat bottom may also be desirable. In other embodiments, watercraft 100 may be of catamaran design, with chambers 7 that might be lowered into water for operation and withdrawn for transportation.

FIG. 3 shows watercraft 100 in body of water 21, with a four point mooring system 50 on bottom 10 securing watercraft 100 in place. In this case, watercraft 100 is in the form of a propelled utility vessel. Shown is an example of optional air compressor 1, pressure storage tank 2, and control valve 5. Chamber front ends 7A for elongated chambers 7 are located for this example in the stern of watercraft 100, symmetric with respect to the centerline of the watercraft 100.

Returning to FIG. 2, watercraft 100 may be located at a desired offshore or lakeshore location, whether under its own power or by the assistance of a tug or other service craft. Watercraft 100 is then oriented for operation and mooring system 50 is deployed. Orientation would involve the steps of directing front ends 7A of chambers 7 (not shown) towards shoreline 29 of interest (i.e., preferably bow away from and the stern towards the shoreline.) and then mooring watercraft 100 in place. Control valve 5 (not shown) may then be operated to discharge compressed gas along chambers 7, generating swells directed to shoreline 29. Meanwhile, watercraft 100 is forced in the opposing direction of the release, its normal and stable direction of forward propulsion, but is maintained in place by mooring system 50. As swells approach the shoreline 29, the depth of the water decreases and swells form cresting wave 24 and eventually beak on shoreline 29. Additional compressed air may be provided using stored air or pressurized air from an optional onboard air compressor 1 (not shown). Upon conclusion of the session of wave generation, mooring system 50 may be recovered, and watercraft 100 may be transported to a second desired location, again, either under its own power or by the assistance of a tug or other service craft (not shown).

The above examples should be considered to be exemplary embodiments, and are in no way limiting of the present invention. Thus, while the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. 

1. An apparatus for generating high volume waves in a body of water, said apparatus comprising; a watercraft having a bow, a stern, a hull, and a mooring system, the watercraft capable of being positioned in a desired location within the body of water and the mooring system capable of fixing the watercraft at the desired location; a wave cannon comprising a tubular chamber having a substantially closed rear end and an open front end, a supply of compressed air fluidly connected with the tubular chamber, and a control valve in fluid communication with the supply of compressed air for operatively controlling the flow of compressed air into the tubular chamber; wherein the chamber is anchored to the hull of the watercraft in a substantially horizontal orientation with the front end of the chamber in fluid communication with the body of water and oriented to discharge in a desired direction with respect to the watercraft, such that actuation of the control valve releases compressed air into the rear end of the chamber and expels water out of the front end of the chamber generating a wave in the body of water and a reaction force against the watercraft; and further, wherein the mooring system is configured for restraining the watercraft in the desired location against the reaction force.
 2. The apparatus of claim 1, wherein the front end of the chamber is oriented to discharge in an aft direction with respect to the watercraft.
 3. The apparatus of claim 1, wherein the chamber is anchored low within the hull of the watercraft.
 4. The apparatus of claim 1, wherein the watercraft is self propelled.
 5. The apparatus of claim 1, wherein the watercraft is a barge.
 6. The apparatus of claim 1, wherein the apparatus further comprises an air compressor in fluid communication with the supply of compressed air.
 7. The apparatus of claim 1, the chamber is anchored to the hull of the watercraft by use of a recoil system.
 8. The apparatus of claim 1, wherein the mooring system comprises one or more anchors and deck tackle.
 9. The apparatus of claim 1, wherein the mooring system is adapted for connection to buoys.
 10. The apparatus of claim 1, wherein the mooring system includes a ballasting submergence system. 